2006 XC90 5T transmission issues doing my head in

mrbolano

hi everyone, long time reader first time poster.

4 weeks back the car (with 225k on it) slipped out of gear turning a corner. I had to turn the engine off and on and it went back into drive but the orange engine warning light and the Transmission Service Required message came on. Drove it home and started reading forums like this. Leading up to this it had been clunking every now and then but not often enough that I was alarm (I'm pretty stupid btw).

Did a pan flush as suggested by half the internet, but first of all found that the drainage bolt I could turn with my fingers and the car has been leaking for I don't know how long. It's had no work underneath it for 2 years so that's a mystery. Only a litre-ish of black fluid came out which explains the dropping out of gear but now I'm wondering how much damage I've done. Topped her up with Penrite ATF but had to guesstimated how much to add because some forums said 3 litres and others 3.5 litres average in a drain from the pan flush. Anyway drove her around the block and she was shifting ok - slight clunk in reverse - but after 15 minutes she dropped out of gear again. Checked levels and was too much ATF in her. Drained 300ml and drove for 30 minutes and no problem so thought, maybe I dodged a bullet? Cleared the transmission service message with some piece of crap Ebay bluetooth thing and dodgy app on my phone.

Anyway……. didn't really drive it much for 2 weeks, just to the shops, but it seemed okay. Rego was due and they did a service, two new front tires, wiper blades etc and oof - $960 in the hole - but it was road worthy.

Transmission warning light came back on 5 minutes after I left the mechanics LOL!

Checked the levels they came back as Low! Added 200ml and again it drove okay. So maybe it still has a leak?

I haven't paid rego yet cause I'm worried I'm registering a dead car. I know the cost of a transmission replacement isn't good sense - more than I paid for it - soI figure I have two options.

Put 6 months rego on it, flush until it runs clean -ish, maybe add Nulon Auto Transmission Treatment (worth it?), monitor it's transmission fluid levels religiously and drive it until it dies.
Take it to the transmission specialist 50km away (I live remote) and get a service and hope for the best (but even he said it sounds pretty bad and I probably need a new gear box.)

Money is the problem. I haven't got any Lol. So Option 2 is not what I'd prefer but maybe I'm missing something in my thinking?

Is it likely/possible it'll keep driving for a while? If I could get 6 more months out of it I could work towards saving to replace it. Dodgy transmissions sometimes just keep on driving yeah? Ugh.

nh2868

The AW55 transmission should have a dipstick on the front - I assume that's how you're checking the level ? When you do a dump and refill you're really only accessing some of the fluid. I needed to do a flush once a week for 3 flushes before the fluid stayed clear red.

The original fluid is Mobil 3309 which is the JWS3309 spec. Penrite full synthetic should be ok, but I've always used Mobil 3309 from a fleabay seller which has worked really well in all our transmissions. Others argue that fluids from Bunnings etc work but the 3309 isn't expensive so I've just stuck to it.

What kills the transmissions is city driving. In other applications (the AW55 is a pretty common transmission across many makers) the torque converter lockup is mainly a freeway function, but Volvo use lockup through all gears so the torque converter clutch gets hammered. 225km isn't high if it's a country car, but could be getting to refresh time if it's a city commuter driven hard (even if that's a previous owner, not you…) I'd leave the additives alone for now, and give it a few more flushes. It takes time to flush out the crap from the solenoids and frictions and get back to clean operation.

The Volvo software can also reset the transmission life counter and adaptations which can help with the shift calibrations. The computer learns the properties of the transmission - what pressure to use for what shift to compensate for slip characteristics and wear - and new fluid may behave differently (hopefully). The slipping out of gear should be either low fluid or sticking solenoid - either way several flushes with the correct fluid shouldn't hurt, and will be the cheapest option with the best potential outcome.